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 Critiquing a critique of rail riding. 
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Master Pine Head
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So, there's this dude, Wayne.

Wayne's a retired engineer (we know how dangerous THAT breed is ;) ) and he's got a website that's basically a brain dump of things he knows about. He has a section for Awana Grand Prix (and Pinewood Derby) cars. He does a lot of analysis of different speed techniques, giving his opinion about whether a particular technique is worth it. Some of the stuff is actually pretty useful, like microscopic examination of axle polishing techniques.

One thing he weighs in on is rail riders. You can see his write-up here. http://waynesthisandthat.com/awana.htm#railriders

He is not supportive of the concept of rail riding. He writes:

Quote:
When the car ran along the left side of the guide rail it was faster, validating the concept. But, when it ran against the right side it was slower. Either the rail sides are not equally smooth, there are protrusions that catch the wheel or the car was aligned with too much pressure on the right side of the rail. What this shows it that to make a rail rider work you'd need access to the track before the race to find out which side of the rail is best and then fine tune the car's alignment to that rail. Even that wouldn't help because cars are required to run on all tracks and one track may be completely different that another. Considering that at most meets the track is strictly off limits prior to the race makes the likelihood of getting a rail rider tuned to that track very small.

Yes, there have been successful rail riding cars that have won championships. But how much of that was luck or the lack of competition? Anyone building a rail rider is going to be well versed in all the other aspects of Awana Grand Prix car construction and their car is likely going to be a high performance vehicle that may very well have won even if it hadn't been aligned as a rail rider.

For myself, this technique has too many risks to advocate.


Now, one frustrating thing is that Wayne is, apparently, busy with some project, so he can't be contacted and doesn't publish his email. If he did, I'd have a lot of questions for him. Since I can't ask him directly, I'll post them here. Maybe Wayne reads Derbytalk.

* How did you build your rail riders? Did you narrow the front end on the DFW? Did you align the rears first? Did you check to make sure that the rears were staying off of the track when you ran?

* What kind of camber are you running on the rear axles and on the front DFW? How many inches of drift is your toe-in set for?

* Are your rail-riders 3-wheelers or 4-wheelers? Have you been attempting to ride the rail on the raised wheel?

* Is one side of your test track strip rougher than the other?

Ball's in your court, Wayne. Defend your anti-rail-riding thesis. :mrgreen:


Mon Feb 03, 2014 6:56 am
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Did you try him at xxxxxxxxxxxx@xxxxxxxxx.net ?
(removed email address ... better for privacy?)

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Mon Feb 03, 2014 11:16 am
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Master Pine Head
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Well, I have /now/. 8)

Stan Pope wrote:
Did you try him at wayneschmidt@earthlink.net ?


Mon Feb 03, 2014 11:23 am
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"WhoIs" is your friend!

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Mon Feb 03, 2014 11:29 am
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Master Pine Head
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Aww, it bounced. Looks like he really doesn't want to be contacted! ;)

Stan Pope wrote:
"WhoIs" is your friend!


Mon Feb 03, 2014 11:40 am
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Vitamin K wrote:
Aww, it bounced. Looks like he really doesn't want to be contacted!
K, I would not worry about it. Many people have questioned rail-riding since it was introduced; MaxV even seemed to question it in the 10th edition (c. 2006) of his tips book:
Quote:
Turned Front Wheel - Believe it or not, a commercial booklet available on the Internet instructs the car builder to turn one of the front wheels inward so that the car rubs against the center guide all the way down the track. Allegedly, this is better than the car bumping the center rail a few times. This is easily proven wrong by testing.
However, by the 11th edition (c. 2008), the "Rail-rider Technique" was a featured strategy.

Wayne's AWANA page has existed for quite some time, and yet cars still ride the rail. And his summary is basically correct: "Aligning a car to always rub against one side of the guide rail is a risky method of trying to increase speed." But if you have some reasonable expectations regarding the condition of the track, then greater risk can bring greater reward. More careful experimentation might cause him to revise his opinion, as other analyses there might also seem questionable or incomplete. For example, the aerodynamics test adds a shroud that does not seem to enclose on the bottom, along with the conclusion that "increased run times by only 0.003 seconds" (~1/2") on average is not a significant amount. Regardless, IMO Wayne's is still an interesting web page.


Mon Feb 03, 2014 12:36 pm
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See email!

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Mon Feb 03, 2014 12:40 pm
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Master Pine Head
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The problem with this type of testing is that not all things are equal, and he's comparing Awana cars, which can't necessarily be applied to BSA cars. His testing, while somewhat scientific, are not absolutely so, nor is his sampling size statistically relevant if he's only performing one test on one car and its parts. Obviously, some things involving the body style, COG, MOI, etc do translate, but the wheels and axles are a bit different. As for rail riding, it's not perfect, but I believe in absence of an intimate knowledge of or ability to tune with the actual race track, it's the best you can do.


Mon Feb 03, 2014 1:25 pm
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Master Pine Head
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Right or wrong, that is a really cool page full of good stuff to think about.

Rail riding is well established as the fastest way to run on a center rail track. I do a low speed friction test when I am aligning and even there it is clear that rail riding is far superior. If the rear wheels hit the rail its like slamming on the brakes.

In my opinion, he jumped to a conclusion that it was track flaws responsible for the time differences he observed riding the right versus left side of the rail when it could have just as easily been rear wheel alignment on his test car. Which leads to an interesting thought - I choose the DFW side when I design the car and its locked in from the beginning (because I drill the NDFW hole high to raise the wheel). But I wonder if anyone waits until the car is essentially complete and does some test runs to determine the best DFW side for that car? In theory, if the rears are drilled perfectly straight the DFW side doesn't matter - but people do stranger things to try to pick up few thousands of a second.

He also didn't say whether he was using negative or positive cant on the DFW.


Mon Feb 03, 2014 1:28 pm
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I posed this question on my sour grapes post yesterday where my son's rr car finished 3rd at districts. "It was the track's fault!" Haha. But maybe this question fits here.

Based on track condition meaning center rail is a jagged mess. At what point is a rr ineffective or at least a wash with a normal 4 wheeler? Or no matter what rr is always better choice?

To be clear I don't think that was the case at our districts.there was no dfw damage indicating bad joints. Rr s have been champions past 4 years on that track. Just a curious question, if you knew beforehand the track was not ideal for rr what would you do differently?


Mon Feb 03, 2014 4:54 pm
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If the car does not fly up out of its lane, then I think that rail guided car will outperform straight alignment ... IF the toe-in is in the ballpark of right and if positive camber is employed. However, if there are deep gouges in the rail that the DFW can ride up on, then the car can, perhaps consistently, fly up and crash. Most of us avoid employing such tracks, but sometimes there is no alternative.

Now, with rail guiding more commonly used, it is not unreasonable for such a car to finish 3rd ... behind two other rail guided cars! The rail guiding practice is not new. It was not new in the 1980's when I overheard a couple of old timers commenting, "That car needs more toe-in!" But is was a much more closely held secret back then.

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Mon Feb 03, 2014 5:27 pm
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Master Pine Head
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If not Jay Wiles around 2000, who then was the 1st to use it? Could it have been Stan Pope? Is RR actually one of the best kept secrets of Pine Car racing????? Hmmm.


Mon Feb 03, 2014 5:45 pm
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tmack wrote:
if you knew beforehand the track was not ideal for rr what would you do differently?
We raced on an old wooden track built in the 1970's. We observed lots of other cars with bad shimmies on that track over the years. Our strategy was to use less toe-in and to be a little less aggressive on the CoM placement than we could have been to maintain a little more traction with the DFW. It worked well for us.
Vitamin K wrote:
Is one side of your test track strip rougher than the other?
If a local unit allows adult / sibling races (ours does), one can try building an identical car with the DFW on the opposite for that race, to see if the other rail edge behaves worse.


Mon Feb 03, 2014 6:41 pm
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LightninBoy wrote:
I choose the DFW side when I design the car and its locked in from the beginning (because I drill the NDFW hole high to raise the wheel). But I wonder if anyone waits until the car is essentially complete and does some test runs to determine the best DFW side for that car? In theory, if the rears are drilled perfectly straight the DFW side doesn't matter - but people do stranger things to try to pick up few thousands of a second.


This actually sounds quite reasonable to me, and I think it merits a little more discussion. Assuming you're not doing iterative, bent-axle alignment, and are instead relying on straight nails and precision-drilled axle holes, I would imagine that, no matter what, you're going to have a little bit of drift one way or the next. Even if it's a quarter-inch over four feet, that's something. It would make sense that you'd want to set up your DFW on the opposite side of the natural drift of the car, so you're not countering forces. :thinking:

One way to do this might be to drill standard axle holes for both front wheels, and then narrow the side for the DFW, and put a serious bend in the non-touching wheel to lift it off of the track. (After you've determined where the natural drift is).


Mon Feb 03, 2014 6:58 pm
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Speedster wrote:
If not Jay Wiles around 2000, who then was the 1st to use it? Could it have been Stan Pope? Is RR actually one of the best kept secrets of Pine Car racing????? Hmmm.

Nope ... my son's cars lost to some who applied DFW toe-in (i.e. rail guiding) before I learned it.

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Mon Feb 03, 2014 7:47 pm
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